#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>

int max3(int a, int b, int c)
{
    int max = 0;
    max = a > b ? a : b;
    max = max > c ? max : c;
    return max;
}

int main()
{
    int a, b, c;
    scanf("%d %d %d", &a, &b, &c);
    float m = (float)max3(a + b, b, c) / (max3(a, b + c, c) + max3(a, b, b + c));
    printf("%.2f\n", m);
    return 0;
}